A Battery Swapping Electric Vehicle (BSEV) can redistribute stored energy between two Battery Swapping Stations (BSSs) through battery migration. Properly balanced electricity storage among BSSs can be utilized as an emergency power supply during disasters. During battery migration, electricity is transferred from a BSS with a higher State Of Charge (SOC) to one with a lower SOC. To regulate energy distribution, a BSEV determines whether to perform battery migration when traveling outside its current area. If a BSEV performs migration every time it exits the current area, frequent and unnecessary inversions of the high-low SOC relationship between BSSs may occur due to excessive migrations. This paper proposes a method to suppress unnecessary battery migrations with small contributions for SOC equalization. The proposed method effectively prevents redundant inversions of the high-low relationship between BSSs.